Air charger for storage tanks



Sept. 28,1948; 5. M. M CARTHY AIR CHARGER FOR STORAGE TANKS Fi led May 5, 1947 2 Sheets-Sheet 1 mm mm m pm "I IJIIIII m m y 9 km Q n 9w 5 Inventor Samuel M. Ma Canhy By @nw and WW8:

Sept. 28, 1 948. s. M. MCCARTHY 2,450,291 AIR CHAR GER FORVSTORAGE TANKS 2 Sheets-Sheet 2 Filed May 5, 1947 I6 I h I6 I *4 2 la 21a 22 l8 luz'eutar I90 Samuel M. Ma Carthy Patented Sept. 2 8, 1948 UNITED STATES 'ATENT' OFFICE '7 Claims.

1 This invention relates to water pressure systems such as are associated with water pumps for supplying dwellings and the like, and more particularly to anair charger for use in connection with well pumps.

Such water pressure systems include a water tankwhich receives Water from the pump and stores the water under pressure. An air cushion is maintained over the top of the water in the tank so as to force the water from the tank through the pipes of the system. As the pressure in the tank is lowered to a predetermined point by drawing water from the tank, the pump is automatically started and water is supplied to'the tank until it reaches a predetermined level and the air pressure is built up to a predetermined point. 'It is common practice in such systems to provide for automatically starting the pump when the pressure in the tank drops to a predetermined point and for automatically stopping the pump when the pressure rises to a predetermined point. It will thus be evident that it is necessary to maintain the quantity of air in the tank within predetermined limits and to replenish air to the tank as it is absorbed or lost, in order to maintain the required cushion of air in the tank.

With most types of air chargers, air is supplied to the tank through the pump, or a connection is required between the air charger and the pump. j The primary object of the present invention, therefore, is to provide an air charger which will automatically supply air to the tank each time the pump is operated, and wherein the air is not drawn through the pump and no connection is required between the air charger and the pump.

A further object is to provide a device of the above kind, wherein the introduction of air is responsive to the pressure in the storage tank.

The exact nature of the present invention, as Well as more specific objects and features thereof, will become apparent from the following description when considered in connection with the accompanying drawings, in which:

Figure 1 is an elevational view showing a characteristic water pressure system equipped with an air charger constructed in accordance with the present invention.

Figure 2 is an enlarged central vertical sectional view of the air charger shown in Figure 1, the movable parts of the air charger being in the positions they assume when the pressure in the storage tank is reduced below a predetermined p in Figure 3 is a view similar to Figure 2'with the movable parts of the air charger in the positions they assume when the pressure in the storage tank is increased above a predetermined point.

Figure 4 is a View similar to Figure 2 showing a modification.

Figure 5 is a view similar to Figure 3 of the modification shown in Figure 4.

Figure 6 is a view similar to Figure 2 of a further modification.

Figure '7 is a view similar to Figure 3 of the modification shown in Figure 6."

Referring in detail to the drawings, 5 indicates the pressure tank into which the water is pumped and stored under pressure. This tank is connected to the discharge side of a pump 6 by a pipe I, and the suction pipe 8 of the pump 6 extends into the'well 9 and has the usual foot valve l0. Pump 6 is operated by an electric motor H which is energized by a pressure controlled switch l2. The arrangement, as usual, is such that when the pressure within the tank 5 falls below a predetermined point, the switch I2 is automatically closed and remains closed until the pressure is built up to an upper predetermined pressure limit, the switch I2 serving to connect the motor I l to a suitable source of current. Water is drawn from the tank 5 through discharge pipe 13. The upper and lower liquid levels in the tank 5 are indicated respectively at M and [5. In other words, when the pressure of the tank 5 falls low enough to start the motor ll operating, the liquid in the tank will be at the line 15 when the normal air supply is present in the tank, and when the pressure in the tank rises high enough to stop the motor II, the liquid in the tank will be at the line M,

The air charger for automatically introducing air into the tank 5 is generally indicated at C, and it includes a chamber it having a constant top communication at I! with the tank 5 substantially at the desired low liquid level 15 in the tank. A fixed piston i8 is provided in the chamber l6, and a reciprocable cylinder I9 is also provided in said chamber and adapted to be moved in one direction by liquid under pressure from the tank 5 along and off of the piston 13 as shown in Figure 3 when the pressure in the tank 5 is increased above a predetermined point. Means, including a check valve 20, provides for a passage of a charge of outside air into the cylinder l9 in response to suction produced within and by said cylinder when the latter is moved in said one direction along the piston IS. The arrangement is such that when the cylinder 19 is moved off of piston IS, the liquid from tank 5 may enter cylinder 19 and force the charge of air from the latter into the chamber I6 for passage into and to the top of tank 5. Spring means is provided for moving the cylinder I9 in the opposite direction onto and along the piston I8 when the pressure in tank 5 is reduced below a predetermined point, such spring means at least including a resilient metallic bellows 2| to which cylinder I9 is attached. The piston l8 includes means which provides for forcing the liquid from the cylinder I'Q into the chamber I 6 when said cylinder I9 is moved in said opposite direction onto and along the piston. This means may consist in the provision of a piston I8 which has a flexible cup member 22 that may yield inwardly out of contact with cylinder I9 under the force of liquid under pressure which is within cylinder I9 when the latter moves onto and along'the piston I8. In other words, as the cylinder I9 moves onto and along piston I8, the water in the cylinder will force its way past the piston and out of cylinder I9. On the other hand, when the cylinder I9 moves in the other direction, along and off of piston I3, the suction thereby produced 3.1 Qy inl l I9 W l ke the s p member 22 n nu contact with the cylinder so that air will be drawn into the latter through the check valve 25) As shown, piston I8 is fixed on the lower end of a rod or stern 2 3 rigid with and depending from the top of chamber I6 centrally of the latter, The rod or stem 1 has a a as 24 therethroush which communicates at its upper end with the check valve 20, mounted in the top of chamber IS.

In the embodiment of Figures 2 and 4, the casing lfi has a detachable bottom 25, and the. lower end of bellows ill has an outtur-ned flange bolted at, g5 between the margin of the bottom 25 and an out-turned flange 2'! provided on the lower end of the body portion of chamber [6. Also, in these embodiments, the bellow 2 I are disposed within a hollow metallic casing forming the chamber I6. and, the cylinder I9 is secured to the top or the bel ws.

ntbe m ment Of F g re 2, y nd s disposed wholly upon the top of the bellows and it has, an ext rna nnul an e a the b om, against which fluid under pressure from tank 5 acts t force e linder I9 downwa d y ga n t. the action of the Sp ing means embodying at least t e, bello s L n th orm of; ur 2 the spring means also includes a helical compression spr ng.- 28 d s os d he b llo s 21 ai sprin bearing at its pper en a n t th bot om of cylinder I9 and at its lower end upon a verticallryadiustable abutment 3 ca ried, b t e tit-.19 end of an adj st g c w 5, h ad dth ough. the bottom 25 of chamber [-6. This arrangement provides for accurate adjustment of the spring means so that the same may be kept at the proper strength for efficient operation of the air charger even though the expansive strength of bellows 2 ,I may vary or decrease after continued use.

In the embodiment of Figure 4., the cylinder I9 is disposed within the upper portion of bellows 2| and has the external annular flange 2;8' at the top thereof, said flange being secured to, the upper end of bel w 24- I this em od m nt the od .3. is shown as a separate attachable member, and the spring 29 and its tension adjusting means, in the form of Figure 2, are dispensed with. By nesting the cylinder I9. within the bellows, the overall height of the chamber I6 may be decreased.

In the embodiment of Figure 6, the chamber I6 is formed in part by a rigid section 32 and in the remainin p t by he ellow 21asho n.

the upper end of bellows 2 I a is bolted at 33 to the underside of section 32, and the cylinder I9a is disposed within and secured to the bottom of bellows 2Ia so that the piston rod 23a is necessarily made longer than in the other two forms of the invention. By thus utilizing the bellows as a Part of the chamber, the construction is simplified and made less expensive although the bellows is not effectively housed and protected as may be necessary or desirable in some'installations.

Other (than specifically described above, the forms of Figures 4 and 6 are similar in essential respects to the construction of [Figure 2, and remaining parts of all of the forms are indicated by similar reference characters.

In explaining the operation of the present air charger, it may be assumed that the pressure in tank 5 is at the desired upper limit and that the cylinder I9, I9 or I9a is in its lowered position off of the associated piston I8. When the pressure in tank 5 is reduced by drawing water therefrom through the pipe I3, the spring means, of the air charger, composed of the bellows or of the bellows andspring, forces the cylinder upwardly onto and along piston I8, any liquid in the W1- inder being forced past the cup member 22 of the piston out of said cylinder and into chamber I6,

- of the latter.

so that the liquid is not trapped in the cylinder and will not prevent its upward movement. The cylinder will then be at its upper limit of move-. pent as shown in Figures 2, 4 and 6. When the pressure in tank 5 has reached a predetermined low level, pump 6 will be thrown into operation so as to. force liquid from the well into ank 5. and thereby build up the pressure within the latter. The liquid under pressure from tank 5 enters, chamber I6 and ultimately reaches a suflicient pressure to force the cylinder I9 downwardly against the action of the spring means. consisting oi the bellows or bellows and spring. When this takes place, suction is produced within the cylinder beneath the piston I8, thereby forcibly drawing outside air into the cylinder past check valve 20 and through passage 24. The cylinder then moves downwardly off of piston I8, and the liquid under pressure rushes into the cylinder so asto force the charge of air out of the latter into, the top of chamber I6, from whence it may pass through the liquid into tank 5 and rise to the top Check valve 20 will of couse pref-v vent passage of air or liquid out of the cylinder or chamber I6 through passage 24 and will only permit entrance of air through passage 24 when the cylinder moves downwardly along piston I8. Should the pressure in tank 5 again be reduced by withdrawing Water therefrom, the spring means consisting of the bellows or the bellows and spring will overcome the, pressure of the liquid in tank 5, and return the cylinder to its upper position so. that the device may again operate to supply another charge of air to thetank 5 in the manner previously described. This cycle of operation is, repeated each time the pump, is started to build up the pressure in the tank 5 and the pressure the tank 5 is subsequently reduced by withdrawal of water therefrom. It will thus be seen that the device provides for introduction of air in the storage tank in response to the pressure within the latter. In other words, the device will automatically supply air to the tank each time the pump isoperated, and such device requires no connection between the same and the pump and draws the air directly from the atmosphere instead of through the pump.

.It w ll be pp nt that h r ent. air charg is relatively simple in construction and will operate eificiently over a long continued period of time without getting out of order or requiring adjustment or repair. Moreover, the device may be readily installed by simply connecting the outlet of the chamber IS with the storage tank 5 at a point substantially at or slightly below the desired lower liquid level in the storage tank as shown in Figure 1. Further modifications and changes in details of construction are contemplated, such as fall within the scope of the invention as claimed.

What I claim is:

1. An air charger for a water system having a storage tank and a pump for supplying water from a well to the tank, comprising a chamber having a constant top communication with the tank substantially at the desired low liquid level in the-tank, a fixed piston in said chamber, a reciprocable cylinder in said chamber adapted to be moved in one direction by liquid under pressure from said tank along and off of said piston when the pressure in said tank is increased above a predetermined point, means including a check valve providing for passage of a charge of outside air into said cylinder in response to suction produced by the cylinder when so moved along the piston, the cylinder moving ofi of said piston so that the liquid may enter the cylinder and force the charge of air from the latter into the chamber for passage into and to the top of the tank, and spring means for moving the cylinder in the opposite direction onto and along the piston when the pressure in said tank is reduced below a predetermined point, viding for forcing the liquid from the cylinder into said chamber past the piston when the cylinder is moved in said opposite direction onto and along the piston.

2. The construction defined in claim 1, wherein the cylinder is of smaller diameter than said chamber and is provided with an external annular flange adapted to be actuated upon by the liquid under pressure from the tank for moving the cylinder in said one direction.

said piston including means pro- 3. The construction defined in claim 1, wherein the cylinder is of smaller diameter than said chamber and is provided with an external annular flange adapted to be acted upon by the liquid under pressure from the tank for moving the cylinder in said one direction, said spring means comprising a resilient bellows having the cylinder attached thereto.

4. The construction defined in claim 1, wherein the cylinder is of smaller diameter than said chamber and is provided with an external annular flange adapted to be acted upon by the liquid under pressure from the tank for moving the cylinder in said one direction, said spring means comprising a resilient bellows having the cylinder attached thereto and nested therein.

5. The construction defined in claim 1, wherein said spring means includes a helical compression spring acting upon the cylinder to move the latter in said opposite direction, and means to adjust the compression of said spring.

6. The construction defined in claim 1, wherein said spring means embodies a resilient bellows forming part of said chamber and having said cylinder attached thereto.

7. The construction defined in claim 1, wherein said check valve is mounted in the top of said chamber, and a piston rod fixed to and depending from the top of said chamber and having the piston mounted upon the lower end thereof, said piston rod having a passage therethrough for conducting the air from the check valve into the cylinder past the piston.

SAMUEL M. MCCARTHY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 776,724 Caverno Dec. 6, 1904 2,183,421 Brady Dec. 12, 1939 2,267,121 McMullen et al Dec. 23, 1941 2,384,770 Ruth Sept. 11, 1945 

